The invention relates to apparatus for filtering air and to apparatus for creating a positive pressure or a negative pressure in a room.
In some circumstances it is desirable to filter the air in a room to remove therefrom infectious airborne particles such as tuberculosis nuclei. This is particularly important in hospital patient rooms, in operating rooms and in home health care situations. However, simple filtering of the air is sometimes insufficient to protect against the spread of disease. Accordingly, it may be necessary to regulate the pressure in the room to achieve the desired result.
Specifically, in hospital patient rooms and home health care rooms, the air in the rooms may already be contaminated. Thus, it is desirable to prevent air in the room from escaping to other rooms in the hospital or home. Allowing the air in the rooms to escape could contaminate the air in other adjacent rooms. One known method of achieving this result is to create a negative pressure in the room relative to the pressure in the adjacent rooms. Thus, if the door to the room is opened, clean air will follow the pressure gradient and will rush into the patient room from the adjacent room or rooms. The inrush of clean air substantially prevents contaminated air from leaving the room and thereby prevents the contamination of the air in the adjacent rooms.
Alternatively, in operating rooms and in other sterile environments, the clean air is already in the operating room and the goal is to prevent contaminated outside air from entering the operating room. Accordingly, a positive pressure is created in the operating room relative to the pressure in adjacent rooms so that if a door opens, clean air will rush out of the operating room thereby substantially preventing contaminated air from rushing into the operating room.
Known systems for effecting these results are typically highly complex and extremely expensive. Moreover, a system installed to create only a negative pressure, or alternatively only a positive pressure, is inherently limited to that particular task and may be limited to operation in a particular room. These limitations restrict the ability of the patient to move from room to room or the ability of the hospital to utilize the room for different kinds of patients or procedures.